Drainage system

A gutter apparatus 501 having a channel 502 defined by walls and an underside, a first wall 503 having an outlet 506 extending from it, such that the gutter outlet is in the side wall. The invention also extends to a drainage system including the gutter apparatus in use on a building having an externally insulated 504 outer wall 303. The a second, inside wall of the gutter is connected to the outer wall of the building, preferably via an insulated fascia element, and a downpipe 601 extends from the outlet and is spaced from the outer face of the external insulation, with the insulation positioned between the downpipe and the outer wall of the building, to prevent cold bridging and water ingress to retrofitted external insulation. The preferably aluminium gutter underside or base may be angled and may be in contact with the top of the insulation, and there may be a sealing membrane of rubber which extends between the fascia and the gutter. The system may include a verge channel extending above external insulation at the roof verge.